Question 1169117

let Kevin's age be {{{K}}} and Mark's age {{{M}}}

given:

Kevin is {{{now}}} four times as old as Mark:

{{{K=4M}}} ....eq.1

 Five years ago, Kevin was {{{K-5}}} years old and Mark was {{{M-5}}} 

and, the sum of their ages was {{{45}}}: so we have

{{{(K-5)+(M-5)=45}}} 

{{{K-5+M-5=45}}}

{{{K+M-10=45}}}

{{{K+M=45+10}}}

{{{K+M=55}}}........solve for {{{K}}}

{{{K=55-M}}}.....eq.2

from eq.1 and eq.2 we have

{{{4M=55-M}}}

{{{4M+M=55}}}

{{{5M=55}}}

{{{M=11}}}
 
go to:

{{{K=4M}}} ....eq.1, substitute {{{M}}}

 {{{K=4*11}}} 

{{{K=44}}} 

so, Kevin is {{{44}}} and Mark is {{{11}}}